Here you can find the source of append(child)
HTMLElement.prototype.append = function append(child) { this.appendChild(child);/*from w w w .j a v a 2 s . co m*/ return this; };
HTMLElement.prototype.append = function(element){ this.appendChild(typeof element === 'string' ? document.createTextNode(element) : element); };
Element.prototype.appendAfter = function(element) { return element.parentNode.insertBefore(this, element.nextSibling); }, false;
Element.prototype.appendBefore = function(element) { return element.parentNode.insertBefore(this, element); }, false;
HTMLElement.prototype.appendFirst = function(el) { if (!el) return; if (this.firstChild) { this.insertBefore(el, this.firstChild) } else { this.appendChild(el);